The cephalosporin antibiotic ceftiofur, named as 7-[2-(amino-1,3-thiazol-4-yl)-2-(methoxyimino)acetamido]-3-[(fur-2-ylcarbo nyl)thiomethyl]-3-cephem-4-carboxylic acid, its alkali metal, alkaline earth metal and amine salts of the carboxylic acid group and easily hydrolyzable ester groups thereof are described and claimed in Labeeuw et al U.S. Pat. No. 4,464,367.
A hydrohalide salt of ceftiofur, particularly the hydrochloride salt thereof, was described and claimed in U.S. patent application Ser. No. 664,651 filed 25 Oct. 1984. A corresponding South African Patent No. 85/7613 has been published disclosing such ceftiofur hydrohalide salts.
Ochiai U.S. Pat. No. 4,278,671 and related U.S. Pat. Nos. 4,510,138 and 4,520,194 disclose some 7-[2-(2-aminothiazol-4-yl)-2-(syn)methoxyiminoacetamido]cephalosporins. Many groups are described for positioning in the R.sub.3 or 3-(R.sub.3 --CH.sub.2 --) cephalosporin molecule position. Among the many such R.sub.3 groups are mentioned hydroxy and mercapto at column 1, lines 67 and 68, but no specific compound such 3-mercaptomethyl type is named therein.
Desacetyl cefotaxime, 7-[2-(2-amino-1,3-thiazol-4-yl)-(syn)-2-methoxyiminoacetamido]-3-hydroxyme thylceph-3-em-4-carboxylic acid, is disclosed in a publication entitled "Disposition of Cefotaxime in Rat, Dog and Man" by C. M. Macdonald, et al in Arzneimittel Forschung Drug Research, 34 (II), No. 12 (1984), pp. 1719 to 1723, but such publication does not disclose the 3-mercaptomethyl compound of this invention or suggest the advantages which we have discovered according to this invention.
Published PCT application WO 82/03395 published Oct. 14, 1982 discloses some therapeutically active organic compounds which exhibit at least one group comprising the structure --S'S"--R, but it does not disclose the cephalosporin compounds claimed here.
Derwent Abstract No. 91799 D/50 of Japanese published application No. J56139-494 published Oct. 30, 1981 of Japanese application No. 042864 filed Apr. 3, 1980 discloses cephamycin disulfide symmetrical dimer compounds but it does not disclose the compounds claimed here.